Simple definition
WP-Cron is the task scheduler built into WordPress.
Technical definition
WP-Cron checks for due scheduled events when WordPress receives requests. On low-traffic websites, tasks may run late; on busy sites, repeated triggers can add overhead. A server cron job can invoke wp-cron.php on a fixed schedule when appropriate.
What is it used for?
Run scheduled publishing, background maintenance and tasks registered by plugins.
Practical example
If scheduled posts are delayed on a low-traffic site, configure a system cron trigger and disable traffic-based WP-Cron only after confirming the new scheduler works.
Common issues
- Plugin or theme conflict
- Incompatible update
- Cache hiding the change